---
layout: page
title: Open Definition [-2.0-]{+2.1+}
---
Version [-2.0-]{+2.1+}
The Open Definition makes precise the meaning of "open" with respect to knowledge, promoting a robust commons in which anyone may participate, and interoperability is maximized.
**Summary:** *Knowledge is open if anyone is free to access, use, modify, and share it — subject, at most, to measures that preserve provenance and openness.*
This essential meaning matches that of "open" with respect to software as in the [Open Source [-Definition](http://www.opensource.org/docs/osd)-]{+Definition](https://en.wikipedia.org/wiki/The_Open_Source_Definition)+} and is synonymous with "free" or "libre" as in the {+[Free Software Definition](https://en.wikipedia.org/wiki/The_Free_Software_Definition) and+} [Definition of Free Cultural [-Works](http://freedomdefined.org). The Open Definition was initially derived from the Open Source Definition, which in turn was derived from the [Debian Free Software Guidelines](http://www.debian.org/social_contract).-]{+Works](https://en.wikipedia.org/wiki/Definition_of_Free_Cultural_Works).+}
The term **work** will be used to denote the item or piece of knowledge being transferred.
The term **license** refers to the legal conditions under which the work is
[-made available. Where no license has been offered-]{+provided.+}
{++}
{+The term **public domain** denotes the abscence of copyright and similar+}{+restrictions, whether by default or waiver of all such conditions.+}
{++}
{+The key words "must", "must not", "should", and "may"+}{+in+} this [-should-]{+document are to+} be interpreted as [-referring to default legal conditions governing use of the work (for -][-example, copyright or public domain).-]{+described in+}{+[RFC2119](https://tools.ietf.org/html/rfc2119).+}
## 1. Open Works
An open **work** [-must-]{+*must*+} satisfy the following requirements in its distribution:
### 1.1 Open License {+or Status+}
The **work** *must* be [-available-]{+in the **public domain** or provided+} under an open
**license** (as defined in Section 2). Any additional terms accompanying
the work (such as a terms of use, or patents held by the licensor)
*must not* contradict the {+work's public domain status or+} terms of the license.
### 1.2 Access
The **work** [-shall-]{+*must*+} be [-available-]{+provided+} as a whole and at no more than a reasonable
one-time reproduction cost, [-preferably-]{+and *should* be+} downloadable via the Internet without charge.
Any additional information necessary for license compliance (such as names of
contributors required for compliance with attribution requirements) *must* also
accompany the work.
### 1.3 [-Open Format-]{+Machine Readability+}
The **work** *must* be provided in a [-convenient and modifiable-] form [-such-][-that there are no unnecessary technological obstacles to-]{+readily processable by a computer and where+} the [-performance-]{+individual elements+} of the
[-licensed rights. Specifically, data should-]{+work can+} be [-machine-readable, available in-][-bulk,-]{+easily accessed+} and {+modified.+}
{++}
{+### 1.4 Open Format+}
{++}
{+The **work** *must* be+} provided in an open {+format. An open+} format [-(i.e., a format with a freely available-][-published specification-]{+is+}{+one+} which places no restrictions, monetary or otherwise, upon its [-use) or, at the very least,-]{+use and+} can be {+fully+} processed
with at least one free/libre/open-source software tool.
## 2. Open Licenses
A **license** {+*should* be compatible with other open licenses.+}
{++}
{+A **license**+} is open if its terms satisfy the following conditions:
### 2.1 Required Permissions
The **license** *must* irrevocably permit (or allow) the following:
#### 2.1.1 Use
The **license** *must* allow free use of the licensed work.
#### 2.1.2 Redistribution
The **license** *must* allow redistribution of the licensed work,
including sale, whether on its own or as part of a collection made from
works from different sources.
#### 2.1.3 Modification
The **license** *must* allow the creation of derivatives of the licensed
work and allow the distribution of such derivatives under the same
terms of the original licensed work.
#### 2.1.4 Separation
The **license** *must* allow any part of the work
to be freely used, distributed, or modified separately from any other part
of the work or from any collection of works in which it was originally
distributed. All parties who receive any distribution of any part of
a work within the terms of the original license [-should-]{+*should*+} have the same rights
as those that are granted in conjunction with the original work.
#### 2.1.5 Compilation
The **license** *must* allow the licensed work to be distributed along
with other distinct works without placing restrictions on these other works.
#### 2.1.6 Non-discrimination
The **license** *must not* discriminate against any person or group.
#### 2.1.7 Propagation
The rights attached to the work *must* apply to all to whom it is redistributed
without the need to agree to any additional legal terms.
#### 2.1.8 Application to Any Purpose
The **license** *must* allow use, redistribution, modification, and
compilation for any purpose. The license *must not* restrict anyone
from making use of the work in a specific field of endeavor.
#### 2.1.9 No Charge
The **license** *must not* impose any fee arrangement, royalty, or other
compensation or monetary remuneration as part of its conditions.
### 2.2 Acceptable Conditions
The **license** [-shall not-]{+*must not*+} limit, make uncertain, or otherwise diminish the permissions
required in Section 2.1 except by the following allowable conditions:
#### 2.2.1 Attribution
The **license** *may* require distributions of the work to include attribution
of contributors, rights holders, [-sponsors-]{+sponsors,+} and creators as long as
any such prescriptions are not onerous.
#### 2.2.2 Integrity
The **license** *may* require that modified versions of a licensed work
carry a different name or version number from the original work or
otherwise indicate what changes have been made.
#### 2.2.3 Share-alike
The **license** *may* require [-copies or derivatives-]{+distributions+} of [-a licensed-]{+the+} work to remain
under [-a license-] the same [-as-]{+license+} or {+a+} similar [-to the original.-]{+license.+}
#### 2.2.4 Notice
The **license** *may* require retention of copyright notices and identification of the license.
#### 2.2.5 Source
The **license** *may* require [-modified works-]{+that anyone distributing the work provide recipients with access+} to [-be made available in a form-]{+the+} preferred {+form+} for [-further modification.-]{+making modifications.+}
#### 2.2.6 Technical Restriction Prohibition
The **license** *may* [-prohibit distribution-]{+require that distributions+} of the work [-in a manner where-]{+remain free of any+} technical measures [-impose restrictions on-]{+that would restrict+} the exercise of otherwise allowed rights.
#### 2.2.7 Non-aggression
The **license** *may* require modifiers to grant the public additional permissions (for example, patent licenses) as required for exercise of the rights allowed by the license. The license may also condition permissions on not aggressing against licensees with respect to exercising any allowed right (again, for example, patent litigation).
{+----+}{+*The Open Definition was initially derived from the Open Source Definition, which in turn was derived from the original Debian Free Software Guidelines, and the Debian Social Contract of which they are a part, which were created by Bruce Perens and the Debian Developers. Bruce later used the same text in creating the Open Source Definition. This definition is substantially derivative of those documents and retains their essential principles. Richard Stallman was the first to push the ideals of software freedom which we continue.*+}